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Title: Linear Chern-Hopf-Thurston conjectureAbstract: The Chern-Hopf-Thurston conjecture asserts that for a closed, aspherical manifold X of dimension 2d, the Euler characteristics satisfies $(-1)^dchi(X)geq 0$. In this talk, we present a proof of the conjecture for projective manifolds whose fundamental groups admit an almost faithful linear representation. Moreover, we establish a stronger result: all perverse sheaves on X […]

Title: Reconstructing schemes from their étale topoi.Abstract: In Grothendieck’s 1983 letter to Faltings that initiated the study of anabelian geometry, he conjectured that a large class of schemes can be reconstructed from their étale topoi. In this talk, I’ll discuss joint work with Magnus Carlson and Sebastian Wolf that proves Grothendieck’s conjecture for infinite fields. Specifically, we […]

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Title: An intrinsic approach to moduli theoryAbstract: A central problem in algebraic geometry is to construct and study moduli spaces of objects of interesting geometric objects. The classical tool for this is geometric invariant theory, which requires you to approximate a moduli problem by an orbit space X/G for some reductive group G acting on […]

Title: Stable Reduction via the Log Canonical Model.Abstract: We will discuss a natural perspective on stable reduction that extends Deligne--Mumford's stable reduction for curves to higher dimensions. From this perspective, we will outline a proof of stable reduction for surfaces in large characteristic.

Title: Du Bois invariants for isolated singularities.Abstract: The Du Bois invariants are natural invariants for singularities. In this talk, I will explain what they are, why they are interesting, and report on recent and ongoing work studying their properties.

Title: A characterization of uniruled Kähler manifolds.Abstract: We adapt Bost's algebraicity characterization to the situation of a germ in a compact Kähler manifold. As a consequence, we extend the algebraic integrability criteria of Campana-Paun and of Druel to foliations on compact Kähler manifolds. As an application, we prove that a compact Kähler manifold is uniruled if and […]

Title: Minimal Log Discrepancy and Orbifold Curves.Abstract: We show that the minimal log discrepancy of any isolated Fano cone singularity is at most the dimension of the variety. This is based on its relation with dimensions of moduli spaces of orbifold rational curves. We also propose a conjectural characterization of weighted projective spaces as Fano orbifolds in […]

Title: Wall crossing for moduli of stable pairs.Abstract: Hassett showed that there are natural reduction morphisms between moduli spaces of weighted pointed stable curves when we reduce weights. I will discuss some joint work with Ziquan Zhuang which constructs similar morphisms between moduli of stable pairs in higher dimension.

Title: Towards a birational geometric version of the monodromy conjecture.Abstract: The monodromy conjecture of Denef—Loeser is a conjecture in singularity theory that predicts that given a complex polynomial f, and any pole s of its motivic zeta function, exp(2πis) is a "monodromy eigenvalue" associated to f. I will formulate a "birational geometric" version of the conjecture, and […]

Title: Hodge symmetries of singular varieties.Abstract: The Hodge diamond of a smooth projective complex variety exhibits fundamental symmetries, arising from Poincaré duality and the purity of Hodge structures. In the case of a singular projective variety, the complexity of the singularities is closely related to the symmetries of the analogous Hodge–Du Bois diamond. For example, the failure […]